Coal Tar Pitch Roofing

Coal Tar Pitch Roofing

A 25-year-old coal tar pitch built-up roof.

What kind of roof is it, coal tar pitch or asphalt? A quick test will show you: put a small piece of the roofing material in lighter fluid, wait a few minutes, and you'll have your answer. The coal tar pitch (on the left) turns the fluid a bright yellow-green, while the asphalt turns it brown.

2. General: A good short introductory article on coal tar pitch roofing, "Coal-Tar Pitch Update" by roof expert Dick Fricklas, is archived on the Buildings.com website. The article is from 2009.

3. General: The Pitch Drop Experiment. Check out the decades-long experiment that's still going on at Australia's University of Queensland, intended to demonstrate the fluidity of pitch. You can watch the pitch in real time as it drips once every 13 years or so. This is at room temperature; it gets much hotter on a roof, decreasing viscosity, and producing the "self-healing" quality for which pitch roofs are esteemed.